1. Field of the Invention
The present invention relates generally to apparatus for removing skins from edible nuts, and more particularly is directed to an improved nut blanching arrangement which results in a greater through-put of blanched nuts and reduced percentages of split, crushed and unblanched nuts.
2. Description of the Prior Art
The prior art is replete with many different types of nut blanching arrangements, some of which are discussed below. An effective nut blanching arrangement should incorporate a number of different features. In practice, the amount of blanching action required to fully remove the outer nut skins without splitting the nuts varies from one type of nut to another and also varies with respect to the size of the nut and other factors. Excessive abrasive action will result in a higher percentage of split nuts, while insufficient abrasive action will produce incomplete blanching. Accordingly, the blanching apparatus should incorporate some adjustment to vary the parameters of the blanching action. The following is a limited discussion of some types of blanching arrangements disclosed by the prior art.
Lewinski U.S. Pat. No. 1,427,000 discloses a peanut blanching arrangement wherein annular ribs are provided around the circumference of counter-rotating cylinders, and an air-tight yieldable covering is stretched over the ribs. The covering may be constructed of rubber to provide frictional engagement with the peanut skins, and the air pressure within the covering is regulated to control the extent to which the rubber covering grips and yields peanuts passing between the rollers.
Lewinski U.S. Pat. No. 1,842,909 discloses a peanut blanching arrangement wherein peanuts are passed between two counter-rotating rollers, and wherein each roller is provided with a plurality of equally spaced and integrally formed annular ribs. A plurality of rubber rings, which may be formed of a soft sponge rubber, are placed between adjacent ribs. This patent basically discloses an arrangement similar to a peanut blancher which is currently in commercial use wherein the peripheral surfaces of counter-rotating rollers are equipped with two urethane pads, one or both of which may be ribbed so that the nuts are forced between the ribs as they are processed by the blancher.
Markley et al. U.S. Pat. No. 2,143,020 discloses a peanut blanching arrangement wherein peanuts are passed between adjacent endless pressure belts. One belt is formed of rubber or a similar resilient material and includes a succession of longitudinally formed, parallel V-shaped grooves. The second pressure belt may be smooth, or may be longitudinally ribbed also.
Green U.S. Pat. No. 2,558,899 discloses a peanut blanching arrangement wherein a conveyor belt is constructed with a plurality of parallel peanut-carrying troughs spaced across its width. Spring fingers are positioned directly over each trough extending downwardly into the slot, and each finger supports a thin cutting blade adapted to slit the peanuts.
Gardner U.S. Pat. No. 2,699,806 is pertinent to the extent that the reference discloses a peanut blanching arrangement wherein shafts carry in spaced relationship a series of pairs of wheels, each of which is provided at its periphery with an annular cushion of sponge rubber or the like.
Gardner U.S. Pat. No. 2,964,080 illustrates a peanut blanching machine including an endless conveyor having a horizontal top reach extending along a predetermined path and adapted to carry nuts thereon. A rubbing apron is disposed in spaced relation above the reach and the nuts are adapted to be frictionally engaged between the two elements to facilitate removal of the skins. The apron is preferably slightly inclined downwardly toward the reach in the direction of movement thereof to trap the nuts between the apron and reach and increase the frictional pressure thereon.
Hind U.S. Pat. No. 3,131,738 discloses a blanching arrangement having a pair of spaced, counter-rotating rollers. A first roller is a nut conveyor roller, and may be formed of a metal billet such as stainless steel or aluminum which is helically threaded or grooved along its length. The second roller is formed with an abrasive surface thereon, and serves as an abrasion roller.
Shaw U.S. Pat. No. 4,023,478 illustrates a nut blanching arrangement wherein nuts are passed between a stationary plate member and a conveyor drum having double spiralled transporting ribbed members radially arranged around its periphery. In this arrangement the spiral ribs are disclosed as being round metal rods welded to the peripheral surface of the drum.
McFarland U.S. Pat. No. 4,034,665 discloses a peanut blanching arrangement wherein a pair of counter-rotating rollers are mounted in spaced adjacent relationship to receive pistachio nuts therebetween. Each roller has longitudinal grooves defining radially disposed, longitudinally extending teeth.